Preliminary data suggest naturally occurring bacteria in the mouth and intestine might trigger the inflammation that causes rheumatoid arthritis, according to findings presented in a press conference at the annual meeting of the American College of Rheumatology on Nov. 8.

"We are testing an old hypothesis with new technology," said Dr. Jose Scher of New York University. The ongoing study is the first to use DNA technology to bypass the cumbersome bacterial culture process. Dr. Scher and his colleagues used DNA sequencing to identify all the bacteria present in the mouths and intestines of study participants. This technology finally allows researchers to explore a long-standing theory that oral and intestinal bacteria might trigger rheumatoid arthritis (RA) by activating Th17 cells.

To date, 90 patients have been enrolled in the study, including 55 adults with RA and 45 healthy controls, Dr. Scher said in an interview. Of these, 22 RA patients and 14 controls have undergone DNA sequencing.